Monica Jansen (Danika Yarosh) is a hidden villainess from the 2019 film,Deadly Switch (alternately titled, Foreign Exchange). She is the daughter of Olivia and Peter Jansen and the sister of Camilla Jansen.
Monica was first encountered by Scottish exchange student Ana (the film's main protagonist) early in the film, when Ana was being pursued by an unknown stalker. Both of them quickly became friends and it was afterwards that Monica offered to drive Ana to her home for protection. Once Ana arrived, she was introduced to Olivia and Peter, who displayed kindly personas towards Ana and revealed that their other daughter, Camilla, had been killed in a car accident.
In actuality, unbeknownst to both parents, Camilla was actually alive and had been in hiding after the aforementioned accident. Camilla was with her best friend, Greta, on that day, but after Greta was killed, Camilla faked her death with Monica's help, doing so to get away from her controlling and emotionally abusive parents. However, Monica turned heel (as did Camilla) during the scheme when they decided to lure in another girl to replace Camilla, and with that, Monica found and targeted Ana, posing as a "stalker" to lure Ana to her so she could befriend her.
Because of Monica's actions, Ana was drugged and held captive by Monica's deranged parents, only to escape with the help of Zelda--Greta's mother. Ana went to Monica's home and confronted the villainess regarding her actions, which Monica defended by stating that "family comes first." In response to Ana asking Monica how she could leave her locked up with her psychotic parents, the evil Monica only said that she had her reasons and that her story to the police would be hard to swallow before lunging at Ana with a knife. Monica ended up knocked out by Ana with a frying pan, and after meeting the real Camilla and seeing her alive, she informed Monica that she would be taking her apartment and that Monica needed to pack and go in to hiding, with the film ending under the indication that Monica followed through with Ana's suggestion and warning.